1. Field of the Invention
The present invention relates to a liquid crystal display device.
2. Description of the Related Art
It is known that a fluorescent tube is used as a backlight of a liquid crystal display device (see Japanese Patent Application Laid-open No. 2001-216807). The fluorescent tube serves as a light source that converts ultraviolet rays generated through electric discharges into visible light beams by irradiating phosphors with the ultraviolet rays. Specifically, electrons released by the discharge collide with mercury atoms. Then, the mercury atoms receive energy from the electrons, and thus the ultraviolet rays are generated. In order that the fluorescent tube may emit light uniformly, it is desirable that the vaporized mercury atoms be dispersed uniformly therein.
Conventionally, a backlight of a general liquid crystal display device using a fluorescent tube has a structure in which, as described in Japanese Patent Application Laid-open No. 2001-216807, the fluorescent tube is retained by a holder at both end portions of the fluorescent tube. The holder is fixed to a frame formed of a metal. The frame serves as a base of the backlight. In this structure, heat of the fluorescent tube is transferred to outer portions thereof through the holder and the frame, and hence the portions of the fluorescent tube retained by the holder may be locally cooled. Mercury liquefies when temperature is decreased, and hence local cooling of the fluorescent tube interferes with uniform distribution of the mercury atoms in the fluorescent tube. As a result, uniform light emission may not be observed.
In the conventional holder for the fluorescent tube, heat retention at the end portions of the fluorescent tube is not considered, and hence there is a problem in that temperature distribution is generated particularly at the end portions of the fluorescent tube. Therefore, the dispersion of the mercury atoms becomes unequal, thereby interfering with uniform light emission.